Ken's POTW

A Few Final Sums

Can you place values at the vertices of a cube (not necesseraly different)
so you end up with a regular die (faces 1 to 6, with 1 opposite 6,
2 opposite 5, 3 opposite 4), when you take the sum over the
vertices of each face? [Also, in a regular die, faces 1-2-3 are clockwise
around one of the vertices. -KD]
Can you find a way to end up with a non-regular die (still faces 1 to 6, but
not all opposite sides give 7 when added)?
[Can it be done with non-negative values? Unique non-negative values? -KD]

Revisiting the Olympic Rings puzzle, here are some more linking rings:

Consider three circles, all intersecting one another, with their centers
at the corners of an equilateral triangle (and radii shorter than the
side of the triangle.) There are seven regions defined by these crossing
circles. Place the numbers 1 to 7 in these regions, such that each circle
has the same total within it.

Consider four circles, all intersecting one another, with their centers
at the corners of a square (and radii shorter than the side of the
square.) There are 13 regions defined by these crossing circles.
Place the numbers 1 to 13 in these regions, such that each circle
has the same total within it.

Linking squares:
Place the numbers 1 to 9 into a 3x3 grid, such that each corner
block of four squares, and the sum of the four independent corner
squares, is the same. (5 equal sums.)